Radio station selector



Oct. 21, 1941. E. H. ALLEN 2,259,719

RADIO STATION SELECTOR INVENTOR nu M uf/v BY f r' l M ATTORNEY Oct. 21, 1941. E. H. ALLEN 2,259,719

RADIO STATION SELECTOR Filed May 20, 1938 3 Sheets-Sheet 2 II'Illllllllllllll INVENTOR :fm2 H Auf/Y ATTORNEY Oct. 21, 1941. E. H. ALLEN 2,259,719-

RADIO STATION SELECTR Filed May 20, 1938 3 Sheets-Sheet 3 lNVENTOR EXPL h. ALLI# BY $4 i ATTORNEY lof the improvements of Patented Oct. 21, 1941 Earl H. Allen, Fanwood. N. I., assignments, to Condenser ration, Newark. N. J., a corporation oi' New Jersey Anuman my zo.' 193s. serai No. 20ans 2 Claims.

'Ihis invention relates to a radio station selector and more particularly to one in which push-button manuals, each representing va given frequency or station, are selectively operable for actuating the tuning unit of the radio receiver.

'Ihe present invention pertains to certain improvements to the type of Radio station selector described in the copending application of Samuel Cohen and Earl H. Allen, Serial No. 193,886, filed March 4, 1938. y

'Ihe broad object of the invention (as set forth in said copending application) centers about the provision of a push-button type of tuning selector for a radio receiver designed to operate mechanically in a way to meet the high accuracy requirements of repeatable tuning selection. Inv

the structure of the present invention, this object is attained .by means of a simplified mechanism, organized to produce a low-cost unit.

The selector of the present invention is intended for use with a variable tuning-unit such as a variable condenser, the rotor of which is movable over a relatively large arc such as 180 degrees. The rotor is connected to an operating member which is common to and operable by any of a plurality of push-button manuals (each representing a given frequency or station), translationally movable over short linear paths. To convert and multiply the short linear movements of the push-button manuals into the large arc rotation of the tuning unit rotor, a motionmultlplying ali-linkage mechanism connecting the operating member with the rotor is employed, which all-linkage mechanism is constructed and designed so as to be characterized by a freedom of play and backlash and a minimum of friction loss, whereby the selector unit is capable of high accuracy repeatable operations.

In the apparatus of the present invention, it is desired that the variable tuning unit be mounted so as to be capable of a direct'drive or operation by the user over the full tuning range in conjunction with the selective operation thereof by the actuation of the selector. A prime object the present invention, therefore, pertains to the construction and design of an all-linkage mechanism connecting lthe so mounted tuning unit rotor with the operating member of the selector, which al1-linkage mechanism is characterized by thedesired substantial freedom of play and back lash and minimum of friction loss which will enable the obtaining of the high accuracy repeat operations of the system.

Tuning units such Vas one class of variable condensers now on the market are manufacturable in the present advanced stage of the art at a comparatively low cost. It is desirable that the selector unit with which such a low-cost tuning unit is combined be manufactured at a correspondingly low cost. It is, therefore. a further object of the present invention to build the selector unit in a simpliiled way without material sacrifice, however. to the attainment of the high accuracy repeatable operations of the selector system. n

A further object of the invention resides in the provision of separable selector units and tuning umts and an all-linkagemechanism for mechanically connecting these units together. which al1-linkage mechanism permits the ready assembly and disassembly ofthe selector unit and the tuning unit. o

To the accomplishment of these objects and such objects as may hereinafter appear, the invention relates to the structural combinations hereinafter sought to be defined in the claims and described in this specication in connection with the appended drawings, in which:

Figure l is a vertical elevational view of the lradio station selector and the tuning unit of the present invention, with parts shown in section to disclose some of the details of construction;

Figure 2 is a similar vertical elevational view thereof, showing the parts in a position of operation different from that depicted in Figure l;

Figure 3 is a left side elevational view thereof, with parts taken in cross-section in the plane of the line 3--3 of Figure l;

Figure 41s a right side elevational view thereof, taken in cross-section in the plane of the line 4-4 of Figure 2;

Figure 5is a cross-sectional view on an enlargedscale of the selector mechanism. taken 40 in cross-section in the plane of the line 5-5 of Figure 2; and

Figure 6 is a perspective view of one of the push-button manuals of the selector mechanism. Referring now more in detail to the' drawings,

45 the radio station selector comprises a selector unit S embodying a supporting frame F with which is xedly associated the separable timing unit T such as a variable condenser. The frame F supports all of the elements of the selector 50 unit S; and the separable tuning unit T carries al1 of the elements of the variable condenser.

The essential components of the selector unit S comprise an operating member O connected by means of a linkage mechanism L to the rotor of 55 the tuning unitT, the said operating member 0 beingcommontnandbeingactuatablebyany of pushutton manuals all colovements of the push-button elements intoa 1 rotation of the rotorofthetuningunitandtodothiswiththatfreedomwtplay and back lash and with that minimum of friction loss which will permit the obtaining of high accuracy repeat operations. ThelinkagemechanismLissodesigned that it is composed only of linkage elements (no gears or pinions). The taining-unit T is arranged and mounted on the frame -F of the selector so as to be capable of direct front drive or operation. andpartsofthelinkagemechanismLarearranged for quick detachment so as to permit the selector unit B.

vide a iirm, rigid and inexpensive support. It consists of an inverted U-shaped body having assembly or disassembly of the tuning unit frame F is built in simple fashion to prothetopwalli andtheoppositesidewalls andl2 braced together by the front and rear wall trips I3 and i4, respectively, which latter are yssbybeingstakedtotheedgesofthe side walls Il and I2. This staking is shown at Il, Il (see particularly Figures 2 to 5), and the staking elements simply comprise lugs integral with the edges of the side walls and |2 re ceived by suitablev apertures in the front and rear wailstrips I3 and I4, which lugs are upset upon or staked to the exterior faces of the wall strips. The top wall of this frame F is suitably provided at its front with a turned-down integral flange portion Il. The frame F may be supported for suitable attachment to the radio cabinet by the angle pieces I1, which may be riveted as at Il, Il to the side walls Il and i2 oi' the frame, the said angle pieces defining supporting legs. Parts of this frame F are otherwise fashioned in the manner hereinafter described to support the operating parts of the selector unit.

The tuning unit T may be of any modern variety: and this is illustrated in the figures as a condenser of the two-gang type. More speciflcally, such a condenser comprises a fabricatedframe I3 having front and rear walls 20 and 2|, two bottom connecting strips 22 and 23 and two side connecting strips 24 and 2|, which parts are suitably staked together. The sidex connecting strips 24 and 2l pendingly support the stator sections s', s', and the frame end walls 20 and 2| are provided with. suitable bearings 2O and 21,

preferably of the ball-bearing type, for supporting the rotor shaft 23, which latter carries the condenser rotor sections r', r. These rotor sections are movable into and out of interleaving relation with the stator sections s', s'. 'I'hese parts composing the tuning unit T thus comprise a unit which is separable from the selector unit;

and the two umts may be assembled by means of the screws 29, 2! (see Figures 3 and 4) which are received by-suitably threaded bosses 33, 3l.

which latter are integral withV (and suitably therefore. the means for linking this operating member to the rotor shaft is made to comprise a mechanism for multiplying the 45 rotation of the operating member to the rotation of the rotor shaft. To controllably eliminate back lash in this part of the system and to reduce the friction loss to a minimum. and also to provide a simplified mechanical structure of low cost, the invention at this point includes connecting the operating member to the condenser rotor by an al1-linkage motion-multiplying mechanism embodying three linkage elements connecting the frame F and the rotor shaft of the tuning unit T, and a fourth linkage element connecting the same with the operating member O, with the relatively movable parts thereof localized to pivot points at which backlash or play is controllably eliminated. i

This al1-linkage motion-multiplying mechanism includes a lever element 3| fulcrumed as at 32 to the downturned frame ange I3 by means of a pivoting rivet (32), the said lever having a partly arcuate shaped arm. 33, a short arm 34 flxedly Joined at its outer end to the shaft 23 and an intervening link element 3l pivotally connected at its'ends to the lever arm 33 and the outer end of the arm 34. 'I'his (three-element) part ofthe linkage mechanism is movable between the extremes of an open link formation shown in Figure 1 of the drawings, to a convolute link -formation shown in Figure 2 of the drawings, the condenser rotor being thereby movable over its full range (180) motion. This linkage mechanism further includes a fourth element in the form of a link 3i which is pivotally connected at its outer ends to a second arm 3l of the lever 3| and to a part of the operating member O.

The operating member O comprises in detail an oscillatable or rockable cradle generally designated as 3U, which is oscillatably mounted in the side walls II and I2 of the frame F. 'I'he cradle simply consists of the upper and lower cam rods 39 and 40, the cross-connectingstrip 4I on one side, and the cross-connecting plate 42 on the other side. The cross-strip 4I and the cross-plate 42 are suitably recessed at 43 and 44 (see Figure 1)' to denne ball-bearing seats receiving the bearing balls 45 and 46, respectively.

'I'he corresponding bearings in the frame F consistl in the seat 41 suitably pressed out of the frame wall il and the seat 48' provided by the inner end of the set screw 49, which latter is threadedly received by the correspondingly threaded boss 50 integral with the frame wall l2, the lock nut Il servingto lock the set screw in adjusted position. The cross-plate 42 is generally of triangular formation and is provided at its front apex with an extension 42' carrying a pivot pin 52 to which the linkage element 3l is connected. This operating member O thus constructed andmounted provides a light weight, inexpensive, readily assemblable, smooth-oscillat ing and no-play structure. -V l 'I'he mode of operation o f the operating mem- `ber O and the manner of connecting the same to the tuning unit T by means of the linkage mechanism L will now be considered more in detail.- A pushing engagement of the upper cam rod 3l of the operating member 0 by a suitable cam or contact member will cause rotation of the cradle 33 in one direction (to cause the condenser rotor to move out of interleaving relation with the condenser stator), while a pushing engagement of the lower cam rod 4I by a suitable cam or contact member will cause rotation of the cradle 36 in the l oppositejor reverse direction (to cause the condenser rotor tomove into interleaving relation with the condenser stator). The cam rods 3l and 46 are also so related that when either cam rod o with the shaft 26 of the tuning unit projecting forwardly so that this shaft may extend through the radio cabinet for direct operation or drive, the'rotor shaft being thus mounted atright angies to the axis of the operating member 0. The

all-linkage mechanism L is, therefore, so designed as to convert and multiply the short arcuate motion of the operating member movable about one axis to a long arcuate motion of the rotor shaft movable about an axis at right angles thereto. The short arm 34 of the linkage mechanism is flxedly joined to the rotor shaft 23 by any .conventional means such as the integral collar and the set screw 53. 'I'he intervening link element 3l is pivotally connected to the aforesaid arms 33 and Il by means of pivot pins 54 and 55 set into the ends of these arms and which are received by suitable orices in the link 35. The fourth .link

element 36 is pivotally connected at one end -to the lever arm 31 by means of a pivot pin 66 set into the end of this arm, and this link 36 twisted through a 90 angle is connected at its other end to the aforesaid pivot pin 52 forming part of the operating member O. The operating member O is thus united or linked to the condenser rotor 2 through the medium of four pivot pins, where all of the loose play or back lash may be or is localized. The play at these four pivot pins is eliminated by additionally coupling the parts by means of the two tensioning springs 51 and 56 arranged respectively and parallel with the links 35 and 36, the said springs being anchored at their opposite ends to extensions of the described pivot pins.

Therefore, by this described means, all play or back lash in the linkagemechanism L is localized and is then eliminated. This linkage mechanism, obviating the use of gears and pinions and vreducing the movable connections to pivot pins of small diameter, reduces the friction loss between a given frequency or station and'each linearly or translationally movable to actuate the operating' member 0,' which latter is common to all the push-button elements. In the exempliilcation'of theinvention shown in the drawings, four push-v button elements are shown, and since these are identical in structure and operation (except that the different ones are adjusted for different stations), only one of these need be described'in detail. It may be premised, however, that Figure 3 shows the manual actuation of the left end manualand Figure i shows the manual actuation of the operating member O and the tunable rotor to a minimum. 'Ihe ball-bearing mounting and the light weight structure of the operating member also serve to eliminate all play and to minimize the friction loss. Also, the linkage elements are exceedingly simple in structure and may be readily assembled for use, thus enabling the manufacture of these parts with uniformity in quantity production and their assembly with speed. ItA will be further noted that after assembling and attaching the tuning unit T to the selector frame F,- the operating member O may be mechanically linked to the rotor shaft of the tuning unit by merely slipping the intermediate link element 35 into position on the pivot pins and by then anchoring to the pivot pins the coupling spring 51. Conversely, when it is desired to remove the condenser unit to detach the condenser unit from v the selector frame, the only preliminary step that need be taken is that of simply detaching the The push-button manuals M comprise a plurality of push-button elements each representing l the right end manual, the parts being so adjusted that in the former case the rotor is moved to a position nearly out of complete interleaving relation and, in the latter case, the rotor is moved to a position nearly into full interleaving relation. It may be also added that the adjustments of the two intermediate manuals shown in the drawings is such that actuation thereof will operate the rotor to different positions both intermediate those depicted respectively in Figures 3 and 4 of the drawings.

Each push-button manual (see particularly the details shown in Figures 5 and 6) comprises a key 59 slidable in keyways 60 and 6I cut, respectively, in the front and rear wall strips I3 and Il -thereon with the upper and lower cam fingers 64 and 65 arranged to cooperate, respectively, with the cam rods 39 and 40 ofthe operating member O. The cam shoe 63 is mounted for rotatable adjustment on a headed stud 66 anchored to the key 59, the mounting being such that when the shoe is unclamped, it will move with rotational freedom on this stud and may thus be moved to any adjusted position. The clamping means for the shoe in its preadjusted position comprises an angular shaped clamp element 61having a wall 66 adapted to clampingly engage the shoe 63, which wall is provided with a rectangular orifice 69 freely received by a lug 1li which is pressed out of the material of the key 59, the said clamp element also including a wall 1| generally at right angles to the wall 66, the wall 66 having a reduced outturned anchoring end 12. A second lug 13 is also pressed out of the material of thekey 59, and both of these lugs 10 and 13 are provided with registering tapped orifices for receiving the locking screw 1l, the inner end of which bears against the wall 1| of the clamp element and the outer end of which carries a push-button element 15. The key 59 is also desirably provided with stop shoulders 16 which are adapted to bear against the inner face of the front wall strip I3 to define the limit of the outward motion of the manual. A tension spring 11 anchored at its opposite ends to the wall strip I3 and the clamp element 61 urges the manual to its outermost or inoperative position.A

By means of this recited construction of the push-button manual, it will be seen that each manual may be preset or adjusted to a given station by loosening the clamp element 61 (effected by counter-clockwise rotation of the pushbutton 15 thereby unclamping the cam shoe 63), by then moving the rotor of the tuning unit T manually'by the operation of the rotor shaft 28 (direct drive thereof) to a given station, by then sans pushingthepush-buttonlluntilthscamngers the the cam rodsllandllandarelockedinpoaitionthereby, and thenclampingtheclampelementt'l (effected by the clockwise rotation of the push-button 1l). Thereafter, push-button operation of the push-button element will repeat the thus obtained setting of the tuning unit rotor. Obviously. the diiferent push-button manuals are preset for different stations.

In addition to the directdrive and the selective actuation of the tuning unit, I alsoprefer to provide an indirect' speed reducing drive operable from the front of the radio cabinet. To this end, the tuning unit 4rotor shaft is provided with a pulley 1l secured thereto, and this is connectedby means of the belt (cord) drive 'II to a spindle Il which is rotatable in spaced bearings in the front wall strip Il, the said bearings being provided by spaced orinces in the wall strip and in a bracket Il riveted to the wall strip, the spindle 8l having a front' extension to which a finger knob l2 is secured, the cord Il being preferably provided with. a tensioning section Il.

'I'he structure and operation of the radio station selector of the invention and the various advantages thereof will in the main be fully apparent vfrom the above-detailed description. It will be seen that the movement of any push-button manual over a short (about inch) linear or translational movement operates the selectormechanism to rotate the condenser rotor to any preset position within its 180 rotation range.

invention dedned in the 4appended claims.

I claim: v l. In a radio station selector, a station tuning device having a stator anda rotor, said rotor i erating member, said operating'member being the rotor, a link connecting said arm with one arm of said lever and a link' connecting the operating member-with the other arm of said lever,

' and a tensioning means in parallel with each This operation is accomplishedfby the simple mechanism described, the parts of which are inter-related so that there is substantial freedom of play and back lash combined with a minimum of friction loss; all to the end there may be obtained a high degree of total accuracy in the repeated operations of the manuals.

All of the manuals M are operable for preselecting a frequency or.station. The tuning unit T may also bel operated manually over the full range by the direct operation of its rotor shaft.

and indirectly by a speedv reducing operation thereof. No gears are employed in the mechanism of the selector; and the elements of the of said links coupling together the elements coupled by said links.

2. In a radio station selector, a station tuning deviceghaving a stator and a rotor, said rotor being movable over a relatively large arc, a rotatable operating member, a plurality of seleef tively operable manuals for 'actuating said operating member, said operating member being movable over a relatively small arc, the axesof said rotor and operating member being at angles to each other, and a four-element motion-multiplying linkage mechanism connecting said operating member with -said rotor, said linkage mechanism comprising a lever fulcrumed on the selector frame, an arm fixed at its cuter end to the rotor, a link pivotally connected at its ends to said arm and to one arm of said lever and a second link pivotally connected at its ends to the operating operating mechanism-of the selector are so de.

signed by their uniformity and simplicity as to be capable of being manufactured in large quantitles and assembled with facility and rapidity. Moreover, all of the operating elements are subioulllcd bi Said links.

member and to the other arm of said lever, the pivots of said second link being at angles to each other, Vand tensioning means in parallel with each of said links coupling together the elements EARLH.ALLEN. 

